Tumor immune microenvironment and nivolumab efficacy in EGFR mutation-positive non-small-cell lung cancer based on T790M status after disease progression during EGFR-TKI treatment.

The efficacy of programmed death-1 blockade in epidermal growth factor receptor gene (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) patients with different mechanisms of acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) is unknown. We retrospectively evaluated nivolumab efficacy and immune-related factors in such patients according to their status for the T790M resistance mutation of EGFR. We identified 25 patients with EGFR mutation-positive NSCLC who were treated with nivolumab after disease progression during EGFR-TKI treatment (cohort A). Programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) density in tumor specimens obtained after acquisition of EGFR-TKI resistance were determined by immunohistochemistry. Whole-exome sequencing of tumor DNA was carried out to identify gene alterations. The relation of T790M status to PD-L1 expression or TIL density was also examined in an independent cohort of 60 patients (cohort B). In cohort A, median progression-free survival (PFS) was 2.1 and 1.3 months for T790M-negative and T790M-positive patients, respectively (P = 0.099; hazard ratio of 0.48 with a 95% confidence interval of 0.20-1.24). Median PFS was 2.1 and 1.3 months for patients with a PD-L1 expression level of ≥1% or <1%, respectively (P = 0.084; hazard ratio of 0.37, 95% confidence interval of 0.10-1.21). PFS tended to increase as the PD-L1 expression level increased with cutoff values of ≥10% and ≥50%. The proportion of tumors with a PD-L1 level of ≥10% or ≥50% was higher among T790M-negative patients than among T790M-positive patients of both cohorts A and B. Nivolumab responders had a significantly higher CD8+ TIL density and nonsynonymous mutation burden. T790M-negative patients with EGFR mutation-positive NSCLC are more likely to benefit from nivolumab after EGFR-TKI treatment, possibly as a result of a higher PD-L1 expression level, than are T790M-positive patients.

Haratani K ，Hayashi H ，Tanaka T ，Kaneda H ，Togashi Y ，Sakai K ，Hayashi K ，Tomida S ，Chiba Y ，Yonesaka K ，Nonagase Y ，Takahama T ，Tanizaki J ，Tanaka K ，Yoshida T ，Tanimura K ，Takeda M ，Yoshioka H ，Ishida T ，Mitsudomi T ，Nishio K ，Nakagawa K ... -  《-》

Impact of EGFR-TKI Treatment on the Tumor Immune Microenvironment in EGFR Mutation-Positive Non-Small Cell Lung Cancer.

The impact of EGFR tyrosine kinase inhibitors (TKI) on the tumor immune microenvironment (TME) in non-small cell lung cancer (NSCLC) is unclear. We retrospectively identified 138 patients with EGFR-mutated NSCLC who underwent rebiopsy after progression during EGFR-TKI treatment. PD-L1 and CD73 expression in tumor cells and tumor-infiltrating lymphocyte (TIL) density at baseline and after progression were determined by IHC. Tumor mutation burden (TMB) was determined by next-generation sequencing. The proportion of patients with a PD-L1 expression level of ≥50% (high) increased from 14% before to 28% after EGFR-TKI (P = 0.0010). Whereas CD8+ and FOXP3+ TIL densities were significantly lower after EGFR-TKI treatment than before, CD8+ TIL density was maintained in tumors with a high PD-L1 expression level. Expression of CD73 in tumor cells after EGFR-TKI treatment was higher than that before in patients with a high PD-L1 expression level. TMB tended to be higher after EGFR-TKI treatment than before (3.3→4.1 mutations/Mbp, P = 0.0508). Median progression-free survival for subsequent treatment with antibodies to PD-1 was longer for patients with a high than for those with a low PD-L1 expression after EGFR-TKI (7.1 vs. 1.7 months, P = 0.0033), and two of five patients whose PD-L1 expression level changed from low to high after EGFR-TKI treatment achieved a PFS of >6 months. EGFR-TKI treatment was associated with changes in the TME of EGFR-mutated NSCLC, and such changes may provide clues for optimization of subsequent PD-1 inhibitor treatment.

Isomoto K ，Haratani K ，Hayashi H ，Shimizu S ，Tomida S ，Niwa T ，Yokoyama T ，Fukuda Y ，Chiba Y ，Kato R ，Tanizaki J ，Tanaka K ，Takeda M ，Ogura T ，Ishida T ，Ito A ，Nakagawa K ... -  《-》

A Randomized Phase II Study Comparing Nivolumab With Carboplatin-Pemetrexed for Patients With EGFR Mutation-Positive Nonsquamous Non-Small-Cell Lung Cancer Who Acquire Resistance to Tyrosine Kinase Inhibitors Not Due to a Secondary T790M Mutation: Rationa

Antibodies to programmed cell death-1 (PD-1), such as nivolumab, have shown promising clinical activity in patients with advanced non-small-cell lung cancer (NSCLC), but their efficacy appears to be less pronounced in patients with such tumors harboring epidermal growth factor receptor gene (EGFR) mutations. Recent findings suggest that patients with EGFR mutation-positive NSCLC who develop resistance to tyrosine kinase inhibitors (TKIs) due to mechanisms other than acquisition of the secondary T790M mutation of EGFR are more likely to benefit from nivolumab treatment, possibly as a result of a higher level of expression of the PD-1 ligand PD-L1, than are patients who are T790M-positive. The WJOG8515L study (UMIN ID: 000021133) is a randomized phase II trial to compare nivolumab with the combination of carboplatin and pemetrexed in patients with EGFR mutation-positive nonsquamous NSCLC who have developed resistance to EGFR-TKIs due to mechanisms other than T790M. Eligible patients are those with stage IV or recurrent EGFR mutation-positive NSCLC who experience disease progression after therapy with more than 1 EGFR-TKI, including gefitinib, erlotinib, or afatinib; they must show no evidence of the T790M mutation on analysis of a tumor biopsy specimen obtained after progression on such EGFR-TKI therapy, or, if T790M is detected, they must again experience progression on subsequent treatment with a third-generation EGFR-TKI. The primary endpoint is progression-free survival (PFS), and secondary end points include overall survival (OS), objective response rate, duration of response, safety, and OS and PFS according to PD-L1 expression level. Recruitment started in May 2016 and is ongoing.

Hayashi H ，Chiba Y ，Sakai K ，Fujita T ，Yoshioka H ，Sakai D ，Kitagawa C ，Naito T ，Takeda K ，Okamoto I ，Mitsudomi T ，Kawakami Y ，Nishio K ，Nakamura S ，Yamamoto N ，Nakagawa K ... -  《-》

Retrospective analysis of antitumor effects and biomarkers for nivolumab in NSCLC patients with EGFR mutations.

Sato M ，Watanabe S ，Tanaka H ，Nozaki K ，Arita M ，Takahashi M ，Shoji S ，Ichikawa K ，Kondo R ，Aoki N ，Hayashi M ，Ohshima Y ，Koya T ，Ohashi R ，Ajioka Y ，Kikuchi T ... -  《PLoS One》

Clinicopathologic Features and Immune Microenvironment of Non-Small-cell Lung Cancer With Primary Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors.

Approximately 20% to 30% of non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-activating mutations are not responsive to EGFR tyrosine kinase inhibitors (TKIs). Although primary resistance to EGFR-TKIs has been attributed to various genetic alterations, little is known about the clinical and immunopathologic features of patients with primary resistance. The tumor immune microenvironment, including tumor-infiltrating lymphocytes (TILs) and programmed cell death ligand 1 (PD-L1), has been reported to play an important role in tumor progression in those with NSCLC. However, few studies have directly focused on the relationship between the tumor immune microenvironment and primary resistance to EGFR-TKIs. The characteristics of 124 NSCLC patients with EGFR mutations who had received EGFR-TKIs were analyzed. Primary resistance was defined as disease progression within 3 months after EGFR-TKI treatment. Tumor specimens obtained before EGFR-TKI treatment were assessed for the density of TILs expressing CD4 or CD8 and for the expression rate of PD-L1 on tumor cells and tumor-infiltrating immune cells, immunohistochemically. Primary resistance was observed in 13.7% of the patients (17 of 124). A significant difference in smoking history was observed between patients with primary resistance and those with non-primary resistance. A lower density of total TILs and negative PD-L1 expression on immunohistochemical analysis correlated significantly with primary resistance, in contrast to that with non-primary resistance. Moreover, the negative PD-L1 expression with low TIL density, indicating immune ignorant phenotype of tumor microenvironment, was observed in those with primary resistance with a significant difference. Smoking and immune ignorance in the tumor microenvironment might result in primary resistance to EGFR-TKIs.

Takashima Y ，Sakakibara-Konishi J ，Hatanaka Y ，Hatanaka KC ，Ohhara Y ，Oizumi S ，Hida Y ，Kaga K ，Kinoshita I ，Dosaka-Akita H ，Matsuno Y ，Nishimura M ... -  《-》